One of the enzymes of the urea cycle, the metabolic pathway transforming neurotoxic amonia produced by protein catabolism into inocuous urea in the liver of ureotelic animals. Catalyzes the formation of arginosuccinate from aspartate, citrulline and ATP and together with ASL it is responsible for the biosynthesis of arginine in most body tissues. {ECO:0000305|PubMed:18473344, ECO:0000305|PubMed:27287393, ECO:0000305|PubMed:8792870}. This is the function of ASS1 (argininosuccinate synthase 1, Ensembl gene identifier ENSG00000130707).